1. Field of the Invention
The present invention concerns magnetic resonance methods and devices for analyzing a joint inflammation, for determining a proteoglycan proportion in the region of the joint, and/or for analyzing osteoarthritis.
2. Description of the Prior Art
Osteoarthritis (OA) is a process of joint deterioration encompassing of various factors and involves the loss of functional capability of the joint. It is not yet possible to perform a reproducible classification or analysis of osteoarthritis that measures the damage of the cartilage and other joint structures (including the synovial fluid). Techniques are indeed known to determine and to quantify a degree of inflammation of the synovial fluid and a degeneration of the respective cartilage structures, but these techniques are not able to supply reproducible results. For example, it is not yet possible to provide such reproducible analysis or quantification of osteoarthritis in an MR imaging procedure.
According to prior art, the following techniques are used for the purpose of analyzing osteoarthritis:
Two-dimensional MR measurements are used to determine the thickness of a layer of tissue damaged by synovitis. In the process, the thickness of the tissue damaged by synovitis is determined manually by a physician performing several MR measurements at different sections of the respective joint and manually measuring the thickness of the layer of tissue damaged. Thus it is almost impossible to reproduce the results since even the same physician in examining his or her results would have difficulties to repeat the MR measurements at the same sections of the joint.
Moreover, it is known to perform a T1 measurement in a specific region of the joint after administering a T1 contrast medium. By means of such a T1 measurement the proteoglycan proportion in the region of the joint is measured that, in turn, is a measured value of the degeneration within the joint. This known determination of the proteoglycan proportion involves the following problems:
It takes at least 30 minutes until an adequate amount of T1 contrast medium has been absorbed in the region of the joint, which results in a respective waiting period for the patient.
In order to guarantee reproducibility it would be important to also perform a T1 measurement before administering the T1 contrast medium. Because of the above-mentioned period of waiting until an adequate amount of T1 contrast medium has been absorbed in the region of the joint, the patient has to be placed twice in a respective magnetic resonance imaging scanner, which is cumbersome, time-consuming and therefore expensive. What is more, it is extremely difficult for the same physician to perform the two T1 measurements before and after administering the T1 contrast medium, if a manual process is used to measure the same region of the joint.
In order to be able to compare subsequent measurements it is important that the T1 measurement is performed in the same region of the joint, which is almost impossible to do if the process is performed manually.
A further problem involves the feeding of the information obtained through the T1 measurement(s) consistently and reproducibly into a rating system.
According to prior art, there exists the further possibility of using a process in which a respective image of the joint is produced by means of a morphologic MR process, and respective tissue alterations of the joint and respective alterations of the associated structures within the joint (for example, the meniscus, ligaments or bones) are analyzed in order to generate an analysis of the osteoarthritis.
In summary the known procedures of analyzing osteoarthritis art are not ideal for providing reproducible results because they are cumbersome and have limited properties.